General Motors and its partner, OnStar, plan to introduce a new feature to GM …

Starting in 2009, police may be able to stop vehicles in their tracks with a simple phone call. The technology would come as part of something that most of us are already familiar with: General Motors' OnStar system. GM and OnStar demoed a prototype today of the new feature, called Stolen Vehicle Slowdown, which will be targeted at... well, stolen vehicles on the road. Stolen Vehicle Slowdown will come as part of OnStar's newest hardware, which will be available in some 1.7 million vehicles in 2009.

"We look forward to having technologies like Stolen Vehicle Slowdown available to aid our officers in apprehending suspected car thieves and keeping our officers, highways and citizens safe," said the national VP of the Fraternal Order of Police, David Hiller. "Since 1996, OnStar has assisted the law enforcement community by helping to locate stolen vehicles."

The OnStar system currently performs a number of useful functions that we've heard so much about on TV commercials. It is often used to locate lost or stolen vehicles via GPS, can locate customers immediately in the event of a car crash, and call 911. It also allows customers to call in to have the car unlocked if they get accidentally locked out. (Anyone want to take bets on this being the most-used OnStar feature?) GM says that it currently receives about 700 requests per month to help find stolen vehicles.

The process for Stolen Vehicle Slowdown would go something like this. A customer calls OnStar to report that his vehicle has been stolen, which would prompt OnStar to locate the car via GPS. OnStar would then provide the car's information and location to law enforcement in the area. The police, when they are able to establish a clear line of sight on the stolen vehicle, can then call into OnStar and request that the car be slowed down remotely. OnStar would then send a signal to the car that would instruct it to reduce engine power, thus slowing the car to an eventual stop.

Stolen Vehicle Slowdown is a significant milestone in another way: now mass-produced cars can be remotely controlled, and GM says that it might sell the technology to other carmakers in the future. And as long as the companies tout that it can cut down on dangerous police chases, it's easy to see why the general public might get excited over it.

But one concern would be whether the police could slow down any car with OnStar capabilities whenever they want—after all, no one wants to be driving along and suddenly have the car forced to a (slow) stop for any old reason. Indeed, there are number of troubling ways in which the new OnStar tech could be misused and abused. But GM says that OnStar customers will have the ability to opt out of the Stolen Vehicle Slowdown feature at any time if they should so choose, although the company says that its research shows that 95 percent of its subscribers want the service for their vehicles.